Propriedades físicas do solo e crescimento de raízes de milho em um argissolo vermelho sob tráfego controlado de máquinas

Abstract

Soil functions can be hampered by compaction induced by inadequate management. Some soil physical properties are indicators of the existence of compacted layers that can affect the root development of crops. Agricultural practices, e.g., planting of cover crops to improve soil properties, can mitigate the compaction-related problems. The aim of this study was to evaluate the physical attributes of soil and plants, grown under controlled conditions. In an Ultisol under no-tillage with two winter cover crops (fallow and oat + vetch) and controlled machine traffic (no traffic -NT, before traffic - BT and after traffic - AT), we evaluated the pre-consolidation pressure, penetration resistance, soil bulk density, porosity, and average diameter of aggregates. Undisturbed soil samples were collected before and after traffic, filled into PVC pots and placed in a greenhouse. Three corn seeds were sown per pot and grown for 25 days under different conditions of water availability. After this period, the leaf area and the fresh and dry matter of corn shoots and roots were determined. Regardless of the layer, bulk density was not affected by the soil cover, but was influenced by machine traffic. Macroporosity in the fallow plot was affected by traffic to a depth of 0.10 m, indicating the reduced capacity of this system to resist disturbances, evidenced also by the lower pre-consolidation pressure. Resistance to penetration increased with depth, and was related to higher density, lower macroporosity and higher pre-consolidation pressure. Without water stress, maize root growth was positively influenced by machine traffic. Under the tested experimental conditions, no-tillage with crop rotation was more resilient to soil disturbances than the other system.